The subject matter described and/or illustrated herein relates generally to protective hoods, and more particularly, to protective hoods for protecting a wearer against hazardous environmental elements. The entire disclosure of application Ser. No. 12/001,572, filed Dec. 11, 2007, titled “PROTECTIVE HOOD” is hereby incorporated by reference herein in its entirety.
Firefighters, rescue workers, civilians, and others working in chemical, biological, nuclear, and other environments sometimes use protective hoods to protect their heads from chemical, biological, radiological, nuclear, or other contaminants that may be present in the environment. A protective hood typically includes a protective head covering that is capable of being attached to a source of breathing air (such as, but not limited to, a powered air-purifying respirator (PAPR) and/or a pressurized air supply). The protective hood may include an outlet that enables gas, including air that has been breathed and any air that has not been breathed, to be expelled from an interior space of the protective hood. If no outlet is provided, gas will typically be expelled from the interior space through a neck opening of the protective hood. However, a neck seal assembly that partially seals the protective hood with the wearer's neck may restrict the flow of gas out of the interior space and thereby cause an overpressure within the interior space that may be uncomfortable for the wearer.
At least some known outlets for protective hoods are elastomeric flapper valves. Although elastomeric flapper valves enable gas to be expelled from the interior space of the protective hood without creating an overpressure within the interior space, the extra raw material and installation labor costs of elastomeric flapper valves may increase the cost of the protective hood. At least some other known protective hoods include one or more holes in the protective head covering to enable gas to be expelled from the interior space. Although less expensive, contaminated ambient gas may leak into the interior space of the protective hood through the outlet openings during movement and/or inhalation of the wearer. Moreover, some movements of the wearer may compress the interior space of the protective hood. Re-expansion of the protective hood may draw contaminated ambient gas through the outlet openings and into the interior space of the protective hood.
There is a need for a protective hood having an outlet that is less expensive than at least some known protective hood outlets and/or that prevents contaminated ambient gas from entering an interior space of the protective hood through the outlet.